<![CDATA[Postpartum depression is a mental health disorder that negatively affects mothers, infants, and families. Health education based on the Theory of Planned Behavior (TPB) may improve preventive behaviors by addressing attitudes, subjective norms, perceived behavioral control, and intentions. This study evaluated the effectiveness of TPB-based health education in improving postpartum depression prevention behaviors among mothers in Badung Regency, Bali. A quasi-experimental study employed a non-equivalent control group design involving 100 postpartum mothers on days 0–7 after childbirth, with 50 participants each in the intervention and control groups. Participants were selected using simple random sampling. The intervention group received TPB-based health education, while the control group received standard health education. Sessions lasted one hour weekly for six weeks. Data were collected using questionnaires before and after the intervention and analyzed descriptively and inferentially. The intervention significantly improved knowledge, attitudes, subjective norms, perceived behavioral control, intentions, and preventive behaviors related to postpartum depression (p < 0.001). A significant difference in postpartum depression levels was also observed between the groups after intervention (p < 0.001), indicating reduced depressive symptoms. These findings demonstrate that TPB-based health education effectively improves psychological and behavioral determinants of postpartum depression prevention. Integrating this approach into postpartum care may strengthen preventive practices and support maternal mental health.]]>
